Spontaneous continuous motor unit single discharges
Related Experiment Video
Updated: Jan 1, 2026
Functional Isolation of Single Motor Units of Rat Medial Gastrocnemius Muscle
Published on: December 26, 2020
Andreas Posa1, Izabela Niśkiewicz1, Valerian Raescu1
1Department of Neurology, University Hospital of Halle, Halle (Saale), Germany.
Introduction:
Motor unit hyperexcitability (MUH) may become manifest in needle electromyography (EMG) recordings as fasciculation potentials, myokymic discharges, or neuromyotonic discharges. Here, we describe a further MUH phenomenon.
Methods:
Needle EMG recordings of the Neurology Hospital of Halle (Saale) stored in a video mode as .wav data between 2000 and 2015 were screened for spontaneous continuous motor unit single discharges (SCMUSD).
Results:
We identified 23 video needle EMG waveforms from 14 patients with SCMUSD. The corresponding motor units discharged at a rate of about 6 H Z (6.3 ± 4.0; range, 1.3-18.1). The coefficient of variation of the discharge rate was 3.5% ± 1.7%. Neurogenic disorders were diagnosed in 12 patients, limb girdle muscle dystrophy was diagnosed in one patient, and stiff-limb syndrome was diagnosed in one patient.
Discussion:
Spontaneous continuous motor unit single discharge, as described here, widens the spectrum of MUH phenomena.
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